Theoretical study of31P NMR chemical shifts for organophosphorus esters, their anions and O,O-dimethylthiophosphorate anion with metal complexes

Abstract

Ab initio and density functional theory (DFT) studies along with gauge-including atomic orbitals (GIAO) have been carried out on 31P NMR chemical shifts for a series of organophosphorus esters, replacing (RO)P=O by (RS)P=O, (RO)P=S and (RS)P=S functionalities, and for O,O- dimethylthiophosphorate ion (PA-) complexed with metal ions (Ag +, Hg2+). Ab initio and DFT results are in good agreement with experimental 31P NMR chemical shifts. It is shown that the major contribution of 31P NMR chemical shifts derives from the total paramagnetic tensor and variation of d orbital population at P atom by d π-pπ bond back-donation.